GHS Signal Words: The Distinction between DANGER and WARNING

June 1, 2013 - No need to panic, at least not yet. But let me remind you that the deadline for training all employees on the changes brought about by OSHA’s adoption of the Globally Harmonized System of Classification and Labeling of Chemicals (GHS) into the Hazard Communication standard is getting closer by the day. And while the December 1, 2013 deadline for getting all mandatory employee training completed may seem a long way off, just remember that it was more than fourteen (14) months ago that the revised OSHA Haz-Com standard was published and the deadline was first announced!

One of the best ways to understand a new (or revised) OSHA standard, I believe, is to prepare to teach a class about the topic. I am already covering this topic when conducting OSHA 10 and 30 hour Outreach training classes. And I just produced and posted on our website a free online GHS training tutorial titled “Understanding the GHS Labeling System” for employers to use for employee training purposes, and am currently working on the companion course on understanding safety data sheets (will be ready soon). And many of you already know that I create and post one free toolbox talk each month on our website related to the GHS training requirements; my goal is to have twelve (12) free GHS-related toolbox talks posted by December 1, 2013 that employers can utilize for employee training. As a result of these efforts, I have come to have a much better understanding of the revised OSHA Haz-Com standard.

When researching the labeling requirements of the GHS system, you will note the requirement that one of two “Signal Words” must appear on all container labels and safety data sheets (SDS’s) for harmful chemicals and products; either “DANGER” or “WARNING”. For many employees (and employers), these two terms may seem to be interchangeable, but once you dig into the standard and its appendices, you can see there is a distinct difference between their use and intent. In a nutshell, the signal word “DANGER” identifies chemicals and products that present, relatively speaking, a greater or more immediate hazard to the worker, whereas “WARNING” identifies chemicals and products that present a lesser (although still potentially harmful) degree of hazard.

To see examples of how manufacturers and distributors determine which signal word to use on a label (and SDS) for a particular chemical or product, I recommend you study Appendix C (titled “Allocation of Label Elements”) of the revised Haz-Com standard; more specifically section C-4. There you will see how the signal word used depends on the hazard “category” a particular chemical or product falls into. For example, materials that fall into categories 1, 2, and 3 in Section C.4.1, Acute Toxicity - Oral, are all toxic or lethal if ingested and therefore require the “DANGER” signal word appear on their container label, while the category 4 chemicals and products, which are merely “harmful” if swallowed, get the “WARNING” signal word. As another example, labels for materials covered in Section 4.4, Skin and Eye Corrosion/Irritation, that are categorized as corrosive (and therefore cause damage) to the skin or eyes are marked “DANGER”, whereas similar materials that are only irritate the skin or eyes are marked WARNING. And later in that appendix you will see how labels on containers of flammable liquids (Section C.14.19) are all marked with the signal word “DANGER”, while combustible liquids (which have a higher flash point and are therefore less likely to ignite at room temperature) are marked “WARNING”. If you really want to get into the nitty-gritty of the specific criteria for categorizing chemicals and products based on their health and physical hazards, those are listed in Appendices A and B of the revised Haz-Com standard.

One other item of interest that should jumps out at you is how the “Hazard Statements” used on the labels (and SDS’s) are tied to the hazard classification (and accompanying Signal Word) of the particular chemical or product. Standardized hazard statements, such as “Extremely Flammable Liquid” or “Fatal if Swallowed” appear on labels that have the “DANGER” signal word, whereas labels bearing the “WARNING” signal word tend to have less urgent hazard statements such as “Combustible Liquid” or “Harmful if Swallowed”.

One more topic to address during training is which signal word should appear on the label for chemicals and products that represent two (or more) significantly-different levels of hazard; for example, a product like Acetone, which is highly flammable (and warrants the “DANGER” signal word) but only slightly irritates the skin (which requires a “WARNING”). In those cases, the signal word “DANGER”, which signifies the higher level of hazard, should appear on the label; but, all of the applicable precautionary statements for both type hazards (flammability and skin irritant) will appear on the label too.

The difference between these two Signal Words is probably already apparent to many of you in the health and safety profession. But I thought it was important to cover this topic anyway since the responsibility for conducting health and safety training falls upon many who may not be aware of this important distinction between Signal Words. And I think you will agree that this is an important thing to make sure the trainer understands before they conduct GHS training for workers. While there will be some considerable effort expended up front in training workers to understand the GHS system, the long-term benefit is it should be simpler for employees (and employers) to understand the hazards of the chemicals and products they are exposed to at work.

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